Apparatus for etching substrate and fabrication line for fabricating liquid crystal display using the same

ABSTRACT

A substrate etching apparatus includes: a cassette to receive a substrate that has finished a previous process, and transfer the substrate; a first robot to take the substrate out of the cassette; a second robot to receive the substrate from the first robot and move the substrate mounted thereon vertically up and down; an etching cassette comprising a support to support the substrate and a holder to fix the substrate loaded from the second robot; a cassette fixing unit to fix at least one or more etching cassettes and being rotated at a pre-set angle to allow the substrate to be disposed perpendicular to the ground; and an etching unit to etch the substrate disposed perpendicular to the ground by the cassette fixing unit.

The present patent document is a divisional of U.S. patent applicationSer. No. 11/952,707, filed Dec. 7, 2007, which claims priority to KoreanPatent Application No. 10-2006-0124994 filed in Korea on Dec. 8, 2006,which is hereby incorporated by reference.

BACKGROUND

1. Field of the Invention

The present disclosure relates to an apparatus and method for etching asubstrate and, more particularly, to a fabrication line for fabricatinga liquid crystal display (LCD) and its fabrication method capable ofquickly etching a substrate by integrating a substrate etching line asin-line in a fabrication line.

2. Discussion of the Related Art

Recently, as diverse portable electronic devices such as mobile phones,PDAs or notebook computers are being developed, a flat panel display(FPD) is increasingly required that is light, thin, short and small andcan be applicable to the portable electronic devices. As the FPD, theLCD, a PDP (Plasma display panel), an FED (Field Emission Display), aVFD (Vacuum Fluorescent Display) and an OLED (Organic Light EmittingDevice), etc., are actively studied, and among them, the LCD isreceiving much attention because of its mass-production techniques,fluidity of its driving unit and implementation of high picture quality.

The LCD is commonly applied-for portable electronic devices, so areduction in its size and weight is requisite to improve portability ofthe electronic devices. There can be several ways to reduce the size andweight of the LCD, and in terms of its structure and currenttechnologies, there is a limitation in reducing essential elements ofthe LCD. The essential elements are quite light, so it is very difficultto reduce the weight of the LCD.

BRIEF SUMMARY

Therefore, in order to address the above matters the various featuresdescribed herein have been conceived. One aspect of the exemplaryembodiments is to provide an apparatus for etching a substrate capableof reducing a weight of a liquid crystal display (LCD) by etching asubstrate or a liquid crystal panel.

Another aspect of the exemplary embodiments is to provide a fabricationline for fabricating an LCD capable of quickly etching a substrate byinstalling a substrate etching apparatus for automatically etching asubstrate or a liquid crystal panel at a fabrication line, and thuscapable of quickly fabricating an LCD.

This specification provides a substrate etching apparatus that mayinclude: a cassette to receive a substrate that has finished a previousprocess, and to transfer the substrate; a first robot to take thesubstrate out of the cassette; a second robot to receive the substratefrom the first robot and move the substrate mounted thereon verticallyup and down; an etching cassette comprising a support to support thesubstrate and a holder to fix the substrate loaded from the secondrobot; a cassette fixing unit to fix at least one or more etchingcassettes and being rotated at a pre-set angle to allow the substrate tobe disposed perpendicular to the ground; and an etching unit to etch thesubstrate disposed perpendicular by the cassette fixing unit.

This specification also provides a fabrication line for fabricating anLCD that may include: an alignment film forming line to receive firstand second substrates and form an alignment film with an anchoringforce; a liquid crystal dropping line to receive the alignmentfilm-formed first substrate and dropping liquid crystal on the firstsubstrate; a sealant coating line to receive the alignment film-formedsecond substrate and costing a sealant; an attaching line to receive thefirst and second substrates and attach them; an etching line to etch theattached first and second substrates; and a processing line to receivethe first and second substrates and divide them into a plurality of unitpanels, wherein the alignment film forms line, the liquid crystaldropping line, the sealant coating line, the attaching line, the etchingline, and the processing line are integrated.

The foregoing and other objects, features, aspects and advantages of thepresent disclosure will become more apparent from the following detaileddescription of the present disclosure when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosure andtogether with the description serve to explain the principles of thedisclosure.

The following constitute a listing of the drawings.

FIG. 1 illustrates the basic structure of a substrate etching apparatusaccording to the present disclosure.

FIGS. 2A to 2C are perspective views for schematically showing thesubstrate etching apparatus according to the present disclosure.

FIG. 3 illustrates an etching solution sprayed region on a substrate assprayed by the substrate etching apparatus in FIG. 2A.

FIG. 4 illustrates a substrate etching apparatus according to thepresent disclosure.

FIGS. 5A to 5C show a substrate etching method using the substrateetching apparatus according to the present disclosure.

FIG. 6A is a perspective view of an etching cassette of the substrateetching apparatus according to the present disclosure.

FIG. 6B is a cross-sectional view of the etching cassette of thesubstrate etching apparatus according to the present disclosure.

FIGS. 7A and 7B illustrate loading of the substrate onto the etchingcassette.

FIGS. 8A and 8B illustrate unloading of the substrate from the etchingcassette.

FIG. 9 is a perspective view showing a different structure of theetching cassette of the substrate etching apparatus according to thepresent disclosure.

FIGS. 10A and 10B are partially enlarged views of the etching cassettein FIG. 9, in which FIG. 10A shows an unloaded state of the substrateand FIG. 10B shows a loaded state of the substrate.

FIG. 11 shows the structure of a general liquid crystal display (LCD).

FIG. 12 is a flow chart showing a method for fabricating an LCDaccording to the present disclosure.

FIGS. 13A to 13E are block diagrams of a fabrication line forfabricating the LCD according to a method for fabricating the LCDillustrated in FIG. 12.

FIG. 14 is an integrated block diagram of the fabrication line forfabricating the LCD according to the method for fabricating the LCDillustrated in FIG. 12.

DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERREDEMBODIMENTS

There can be several factors that play a role in determining a weight ofa liquid crystal display (LCD), and among them, a glass substrate of theLCD is the heaviest component. Thus, it would be effective to reduce theweight of the glass substrate to reduce the weight of the LCD.

In general, the glass substrate is etched by an etchant (etchingsolution) such as an HF. Namely, the glass substrate is put in acontainer filled with an etchant to etch a surface of the glasssubstrate. However, in this method, because of non-uniformity of thesubstrate itself, the substrate is not evenly etched, and in addition,impurities generated during the etching process are attached on thesubstrate, making the surface of the substrate uneven. Moreover, anexcessive use of the etchant leads to an increase in costs and causesthe problem of an environmental contamination.

In one embodiment, the substrate can be loaded on a conveyer and theetchant can be applied to etch the substrate while moving the substrate.In this case, however, the etchant remains at a portion of the surfaceof the substrate loaded on the conveyer, over-etching that portion ofthe substrate, which results in an unevenly etched substrate on thewhole.

Therefore, in the present disclosure, the substrate is disposedperpendicular to the ground and the etchant is sprayed to both surfacesof the substrate to uniformly etch the entire substrate. FIG. 1 shows abasic concept of the apparatus for vertically etching the substrate.

The etching of the substrate 1 can be made in a state such that twoglass mother substrates are attached or by the unit of display panel.Namely, two glass mother substrates such as the LCD or a PDP (PlasmaDisplay Panel) can be etched in an attached state or the substrates canbe etched by the unit of attached panels. In the present disclosure, theetching apparatus can automatically etch the substrate transferred froma previous processing line, so by applying the etching apparatus to thefabrication line of the display panel, the fabrication line can becompletely automated. Namely, the substrate, which has undergone theprevious process, is automatically inputted to the etching line, etchedand then outputted so as to be automatically transferred to the previousfabrication line. As the fabrication line is automated, the fabricationof the display panel can be quickly made and the fabrication efficiencycan be considerably improved.

In addition, the substrate 1 can be etched by the unit of glass mothersubstrate or by the unit of processed glass substrate. Namely, the glassmother substrate fabricated during the glass fabrication process isetched to have a desired weight and thickness and processed to be usedas a substrate of the flat panel display device such as the LCD. Ingeneral, the flat panel display device includes two attached glasssubstrates, so its strength can be higher than a single glass substrate.Thus, because it can be fabricated to be thinner than when using asingle glass substrate, the weight of the glass substrate can beconsiderably reduced.

The etching of the glass substrates are generally performed on theattached mother substrates. In order to improve the efficiency infabricating the flat panel display device such as the LCD, requiredelements such as thin film transistors and color filters are formed onthe two facing mother substrates, and then the mother substrates areattached and cut into unit panels, forming respective display panels. Inthe present disclosure, etching of the substrate is made by the unit ofthe attached mother substrates before being cut into the unit panels forthe following reasons.

When the substrates are etched, the etching degree is limited. If thesubstrate is over-etched to become too thin, the substrate would bedamaged during the fabrication process. Thus, the glass substrate islimited in its etching by the unit of the mother substrate. However,when the two substrates are attached (or in case of the attached glasspanels), the substrates can have stronger force to tolerate an impactalthough they are etched more than the mother substrate, so the mothersubstrates can be etched more to reduce the weight when the displaypanels are fabricated.

In the present disclosure, the etching targets etched by the etchingapparatus can be unit mother substrates, processed substrates, anddivided unit panels without being limited to the attached mothersubstrates. Accordingly, the term “substrate” used hereafter will coverthe attached mother substrates, the glass mother substrates, theprocessed substrates, and the divided unit panels.

As shown in FIG. 1, the vertical etching apparatus 10 includes sprayplates 12 disposed at uniform intervals, the substrates 1 being disposedtherebetween; a plurality of nozzles 13 formed on the spray plates 12;and an etchant storage tank 17 for supplying an etchant solution to thespray plates 12. Because the interior of the spray plates 12 are empty,the etchant of the etchant storage tank 17 is supplied to the sprayplates 12 through a supply pipe 15.

The etchant supplied into the interior of the spray plates 12 is sprayedonto the surface of the substrates 1 by the nozzles 13 to etch thesubstrates 1. Because the substrates 1 are positioned between the sprayplates 12, the etchant sprayed from the nozzles 13 of the spray plates12 positioned at both sides thereof reaches both sides of the substrates1 and etches both sides of the substrates 1.

The number and interval of the nozzles 13 of the spray plates 12 aredetermined depending on the size of the substrates 1 to be etched andthe distance between the spray plates 12 and the substrates 1. Anynumber or any interval, however, can be possible so long as the etchantcan be evenly sprayed to the substrates 1.

In the etching apparatus, the substrates 1 are etched by uniformlyspraying the etchant onto the substrates 1 disposed to be perpendicularto the ground. Thus, the etchant sprayed to the substrates 1 flows downby gravitation, leaving no etchant remaining on the substrates 1.Because the etchant does not remain on a particular portion,over-etching of a particular portion can be prevented.

The spray plates 12 extend from a lower base in an upward direction sothe substrates 1 are received from the upper side and disposed betweenthe spray plates 12, but without being limited thereto, the base can bepositioned at the upper side and the spray plates 12 extend in adownward direction. In that case, the substrates 1 can be received fromthe lower side and disposed between the spray plates 12, or the sprayplates 12 can be lowered at both sides of the substrates 1.

FIGS. 2A and 2B are perspective views for schematically showing thesubstrate etching apparatus according to the present disclosure.

As shown in FIG. 2A, as for the length and height of the spray plates 12positioned at both sides of the substrate 1 to be etched, the sprayplates 12 may have the same area as that of the substrate 1 or be largerthan the substrate 1, so that the etchant can be sprayed over the entiresurface of the substrate 1 at a uniform pressure, thus quickly etchingthe substrate 1.

FIG. 2B shows a substrate etching method when the size of the sprayplates 12 with the nozzles 13 formed thereon is smaller than that of thesubstrate 1. In such an etching apparatus, because the size (or width)of the spray plates 12 is smaller than that of the substrate 1, inetching the entire surface of the substrate 1, the spray plates 12 arereciprocally moved at a certain speed from one side to the other side tospray the etchant onto the substrate 1. The reason for this is asfollows.

FIG. 3 shows spray regions (R) of the etchant sprayed onto the substrate1 through the nozzles 13 of the spray plates 12. As shown in FIG. 3, theetchant sprayed from the nozzles 13 reaches certain regions of thesurface of the substrate 1. In order to spray the etchant from thenozzles 13 of the spray plates 12 over the entire surface of thesubstrate 1 to etch it, one spray region (R) of the etchant sprayed fromeach nozzle 13 should overlap with another spray region (R) of etchantsprayed from each adjacent nozzle 13 to prevent generation of a regionwhere the etchant is not sprayed. In this case, however, when theetchant is sprayed from the adjacent nozzles 13 in the overlappingmanner, more etchant is applied to the etchant overlap regions (S),over-etching them, causing the substrate 1 to be unevenly etched as awhole.

In order to form the spray regions (R) over the entire surface of thesubstrate 1, the number of nozzles 13 of the spray plates 12 increases,which means that the etchant sprayed through the nozzles 13 alsoincreases. Thus, the etchant is excessively used, which increases costand causes environmental contamination.

However, when the spray plates 12 are disposed at one side of thesubstrate 1 and spray the etchant while moving at a certain speed, sprayoverlap regions (R) are not generated, so uneven etching of thesubstrate can be prevented. In addition, because the etchant is sprayedfrom the spray plates 12 at a uniform pressure and the spray plates 12move at a uniform speed, the etchant is applied over the entire surfaceof the substrate 1, evenly etching the substrate 1. In this case, thespray plates 12 can be reciprocally moved several times by certainperiods to spray the etchant onto the substrate 1 to perform etchingthereon.

As stated above, the spray plates 12 have the same area as or a largerarea than that of the substrate 1 to spray the etchant over the entiresurface of the substrate 1 through the nozzles 13 at one time. Or, thespray plates 12 having a smaller area than that of the substrate 1 aremoved along the substrate 1 or vibrated at certain periods to spray theetchant to the substrate 1 to perform the etching thereon. Controllingthe area of the spray plates 12 or moving the spray plates 12 is toevenly spray the etchant onto the substrate to thus evenly etch thesubstrate. Thus, the etching apparatus may have any construction so longas it can uniformly spray the etchant to the substrate 1.

For example, when the spray plates 12 have an area smaller than that ofthe substrate, the intervals of nozzles 13 can be controlled to evenlyapply the etchant over the entire surface of the substrate 1, or thespray plates 12 can be reciprocally moved one time or several times withrespect to the side of the substrate 1 to spray the etchant such as toevenly etch the substrate 1.

With reference to FIG. 2C, several spray plates 12 having a smaller areathan that of the substrate 1 can be provided to be moved or reciprocallymoved along one direction of the substrate 1 to spray the etchant on thesubstrate 1. Also, the spray plates 12 can be vibrated at a certainangle or at certain periods to spray the etchant from the nozzles 13 toa larger area, thus evenly spraying the etchant over the entire surfaceof the substrate 1.

In the present disclosure, because the etching apparatus may beautomated, the efficiency of the substrate etching can be improved. Inother words, the efficiency is due to the loading to or unloading fromthe etching apparatus being automatically performed by the robot byinterworking within the overall fabrication lines, not manually by anoperator. As the substrates are automatically loaded to and unloadedfrom the etching apparatus, not only the etching efficiency can beimproved but also the etching apparatus (or the etching line) can beintegrated with the previous processing line or the following processline.

FIG. 4 illustrates an automated substrate etching apparatus according tothe present disclosure. As shown in FIG. 4, the substrate etchingapparatus according to the present disclosure includes: a cassette 20for receiving a substrate 1; a first robot 30 for extracting thesubstrate 1 received in the cassette 20; and a second robot 35 forreceiving the substrate 1 extracted by the first robot 30 andtransferring it to an etching cassette 44.

The cassette 20 is transferred from a previous process. That is, thesubstrate 1 processed in the previous process is transferred in thecassette 20. The first robot 30 includes a rotational shaft 32 and arobot arm 33. The substrate 1 mounted on the robot arm 33 is mounted ona substrate mounting part 36 of the second robot 35 according to arotation of the rotational shaft 32. The second robot 35 includes avertically movable extending shaft 37 that moves the substrate 1 mountedon the substrate mounting part 36 formed at its end portion in avertical direction.

The substrate 1 loaded from the second robot 35 is fixed on the etchingcassette 44, and the etching cassette 44 is fixed at a cassette fixingunit 40. Multiple units of etching cassettes 44 are fixed at thecassette fixing unit 40 at pre-set intervals and rotated by 90 degreescentering about a rotational shaft 41 formed at an end portion of thecassette fixing unit 40. Namely, the substrate 1 fixed at the etchingcassette 44 in the horizontal direction of the ground by the first andsecond robots 30 and 35 is disposed to be perpendicular to the groundaccording to a rotation of the cassette fixing unit 40. The substrate 1disposed to be perpendicular to the ground is transferred to the etchingapparatus through a conveyer 50 and etched.

FIGS. 5A to 5C show a substrate etching method using the substrateetching apparatus according to the present disclosure. First, as shownin FIG. 5A, when the cassette 20 with the substrate 1 received thereinis transferred, the robot arm 33 of the first robot 30 is carried intothe cassette 20 to take the substrate 1 out of the cassette 20. Thesubstrate 1 received in the etching apparatus can be a substrate whichhas undergone various processes. For example, the substrate 1 is theglass substrate itself, or a substrate of a unit area which hasundergone a cutting process in which the glass original plate is cut toparticular areas, or can be a substrate processed to have a particularshape. In addition, the substrate 1 can be two attached mothersubstrates or a unit panel obtained by cutting the attached substrates.The process may include every process in which the glass substrate canbe processed without being limited to a particular process.

As shown in FIG. 5B, the substrate taken out of the cassette 20 by thefirst robot 30 is mounted on the substrate mounting part 36 of thesecond robot 35 according to the rotation of the rotational shaft 32 ofthe first robot 30. Because the second robot 35 is disposed to bemovable up and down in the etching cassette 44, as the second robot 35is lowered, the substrate 1 loaded on the second robot 35 by the firstrobot 30 is fixed on the etching cassette 44.

The etching cassette 44 fixes the loaded substrate 1 and transfers thefixed substrate 1 into an etching unit to actually perform etchingthereon. The etching cassette 44 automatically fixes the substrate 1 andtransfers it into the etching unit, thereby making the overall etchingprocess is line in-line. The etching cassette 44 is not limited to aparticular structure, but may have any structure so long as it caneffectively fix or secure the substrate 1.

FIGS. 6A and 6B show one example of the etching cassette 44 employed forthe etching apparatus. As shown in FIGS. 6A and 6B, the etching cassette44 includes a cassette body 45, a plurality of supports 46 formed on thecassette body 45 and supporting the loaded substrate 1; and holders 48installed on the cassette body 45 and fixing the loaded substrate 1. Thesupports 46 are formed at certain intervals to support the loadedsubstrate 1 as their upper surfaces contact with the bottom surface ofthe substrate 1. In this case, the number of supports 46 may varydepending on the size of the cassette body 45, namely, the size orweight of the substrate 1 to be etched. The supports 46 can be formed onboth facing sides of the cassette body 45 or can be formed on four sidesthereof.

The width of the support 46 varies depending on the size and the weightof the substrate 1 or the number of supports 46, and the length of thesupport 46, namely, the length extending to the substrate, correspondsto a width of a dummy region that is not used when the substrate 1 isused for a particular purpose.

The holders 48 fix the substrate 1 loaded on the etching cassette 44. Asshown in FIG. 6A, the holders 48 are made of a material which has goodelasticity and is thin such as a plate spring, so as to be moved in aninward direction by pressure. However, the holder 48 according to thepresent disclosure is not limited to such a structure. The illustratedstructure is an example of the holder 48 according to the presentdisclosure and, substantially, the holder 48 can be implemented invarious shapes.

Multiple holders 48 are formed in the etching cassette 44. The holders48 can be formed at both facing sides of the cassette body 45, can beformed at four sides thereof, or can be formed corresponding to thesupports 46. The holders 48 and the supports 46 are formed at the samepositions of the etching cassette 44 to face each other, or can beformed at different positions. In particular, the holders 48 and thesupports 46 are formed in crisscross relation to apply a force todifferent regions of upper and lower surfaces of the substrate 1.Because the holders 48 and the supports 46 are formed crisscross (or inzigzags), only one-directional force is applied to the region where theholders 48 and the supports 46 contact with each other, so when thesubstrate 1 is stood to be perpendicular to the ground, a slight gap canbe generated between the substrate 1 and the holders 48 and between thesubstrate 1 and the supports 46. When the substrate 1 is etched, theetchant may infiltrate through the gap between the substrate 1 and theholders 48 and the gap between the substrate 1 and the supports 46, so aparticular region of the substrate 1 contacting with the holders 48 andthe supports 46 can be etched.

The loading of the substrate 1 to the etching cassette 44 will now bedescribed with reference to FIGS. 7 and 8. FIGS. 7A and 7B show loadingof the substrate 1 to the etching cassette 44, and FIGS. 8A and 8B showunloading of the substrate 1 from the etching cassette 44.

In loading the substrate 1 to the etching cassette 44, as shown in FIG.7A, when the substrate 1 is mounted on the substrate mounting part 36 ofthe second robot 35 according to the rotation of the first robot 30, theextending shaft 37 of the second robot 35 is lowered. Then, as theextending shaft 37 is lowered, the substrate 1 mounted on the substratemounting part 36 is also lowered and the edges of the substrate 1contacts with the holders 48.

As the extending shaft 37 of the second robot 35 is lowered, thesubstrate 1 mounted on the substrate mounting part 36 is also loweredand the holders 48 contacting with the substrate 1 move toward the innerside, namely, toward the cassette body 45 by virtue of the weight of thesubstrate 1. As the holders 48 are moved toward the cassette body 45,the substrate 1 is also moved in a downward direction in a state ofbeing in contact with the holders 48, and then mounted on the supports46 upon completely passing by the holders 48 as shown in FIG. 7B.Because the pressure to the holders 48 by the weight of the substrate 1is removed, the holders 48 return to their original shape by elasticityand the lower portions of the holders 48 contact with the upper surfaceof the substrate 1, securely fixing the substrate 1.

With reference to FIG. 8A, when the substrate 1 is unloaded from theetching cassette 44, the extending shaft 37 of the second robot 35 islifted to allow the substrate mounting part 36 to contact with the lowersurface of the substrate 1. Subsequently, the extending shaft 37 iscontinuously lifted to allow the substrate 1 to be moved up in an upwarddirection. In this case, because the upper surface of the substrate 1fixedly contacts with the holders 48, the holders 48 are pressed as thesubstrate 1 is moved up. Then, the holder 48 is contracted toward thecassette body 45, and such a contact is made when the substrate 1 ismoved up and continues until the substrate 1 does not contact with theholders 48.

As shown in FIG. 8B, when the substrate 1 is moved up further, thesubstrate 1 completely released from the etching cassette 44 and, at thesame time, the holders 48 are returned to their original shapes byelasticity.

As mentioned above, the substrate 1 is fixed in the etching cassette 44as the holders 48 are contracted by gravity, and released from theetching cassette 44 as the holders 48 are contracted by the liftingforce of the second robot 35. Accordingly, the substrate 1 can be loadedto the etching cassette 44 so as to be fixed or unloaded from theetching cassette 44 so as to be released by the second robot 35 withoutany additional operation.

FIG. 9 shows an etching cassette 44 with a different structure employedfor the etching apparatus according to the present disclosure. As shownin FIG. 9, the etching cassette 44 includes a cassette body 45, aplurality of supports 46 formed in the cassette body 45 and supportingthe substrate 1 loaded thereon; a clamping 52 installed at the cassettebody 45 and fixing the loaded substrate 1; and a clamping driving unit51 for fixing the substrate 1 by operating the clamping 52.

The supports 46 are formed at uniform intervals on the cassette body 45and support the substrate 1 such that their upper surfaces contact withthe bottom surface of the substrate 1. In this case, the number ofsupports 46 may vary depending on the size or weight of the substrate 1to be etched. In addition, the supports 46 can be formed on both facingsides of the cassette body 45 or can be formed at four sides thereof.

In addition, the width of the support 46 varies depending on the sizeand the weight of the substrate 1 or the number of supports 46, and thelength of the support 46, namely, the length extending to the substrate,corresponds to a width of a dummy region that is not used when thesubstrate 1 is used for a particular purpose. The clamping 52 and thesupports 48 can be formed at the same positions to face each other orcan be positioned at different positions, for example, between eachother so as to be crisscross or in zigzags. The clamping 52 can berotated by the clamping driving unit 51 to load and fix, or unload andrelease, the substrate. In this case, although not shown, the cassettebody 45 may include a sensor for sensing loading or unloading thesubstrate 1 to or from the etching cassette 44 to drive the driving unit51.

FIGS. 10A and 10B are partially enlarged views of the etching cassette44 in FIG. 9. FIG. 10A shows an unloaded state of the substrate from theetching cassette 44 and FIG. 10B shows a loaded state of the substrate 1to the etching cassette 44. The method for fixing the substrate 1 by theetching cassette 44 will now be described.

As shown in FIG. 10A, the clamping driving unit 51 is installed at anupper surface of the cassette body 45, and a plurality of connectors 54are formed at one side of the clamping driving unit 51. The clamping 52is fixed at the connector 54. A fixing pin 55 is installed at an endportion of the clamping 52 and fixed at the connector 54. A rotatablepin 57 a is provided in the clamping 52 and a guide groove 57 b alongwhich the rotatable pin 57 a moves is provided at the cassette body 45,so as to be fixed at the cassette body 45 such that the clamping 52 canbe rotated centering around the rotatable pin 57 a as the rotatable pin57 a moves along the guide groove 57 b. In other words, when theclamping 52 is rotated, the rotatable pin 57 a moves along the guidegroove 57 b, so the clamping 52 can be smoothly rotated.

Two magnets 58 a and 58 b are disposed at one end portions of theclamping 52 and another four magnets 59 a, 59 b, 59 c and 59 d are alsodisposed at the connector 54, which are attached by magnetism with thetwo magnets 58 a and 58 b of the clamping 52. Because the magnets aredisposed at the clamping 52 and the connector 54, the clamping 52 can befirmly fixed to the connector 54 by the magnetic force of the magnets.

A plurality of clampings 52 are formed at the etching cassette 44. Theclampings 52 can be formed at both facing sides of the cassette body 45or at four sides of the cassette body 45, or can be formed correspondingto the supports 46.

With reference to FIG. 10A, when the substrate 1 is not loaded on theetching cassette 44, the clamping 52 is disposed to be substantiallyparallel to one side of the cassette body 45, namely, to the clampingdriving unit 51. In this case, the clamping 52 is fixed by the magneticforce between the first magnets 58 a and 58 b formed at the end portionof the clamping 52 and the corresponding second Magnets 59 a and 59 d ofthe connector 54.

With reference to FIG. 10B, when the substrate 1 extracted from thecassette 20 by the first robot 30 is loaded to the etching cassette 44by the second robot 35, the loading of the substrate 1 is sensed by asensor (not shown) installed at the cassette body 45, and at the sametime, the clamping driving unit 51 starts to move to one side, namely,to the opposite side of the region of the cassette body 45 where thesubstrate 1 is loaded. Namely, the clamping driving unit 51 starts tomove to an outer side of the cassette body 45. Although not shown, aguide unit for guiding the clamping driving unit 51 such as a guide railcan be formed at the cassette body 45 in order to move the clampingdriving unit 51 by a driving unit such as a motor. Various types ofsensors can be used. For example, an optical sensor can be used by usinga difference of transmittance of light that transmits through thesubstrate 1 or a load sensor for sensing a load when the substrate 1 isloaded to the cassette body 45 can be also used.

As the clamping driving unit 51 moves, the connector 54 is moved, andaccordingly, the end portion of the clamping 52 connected with theconnector 54 also moves by the fixing pin 55. Meanwhile, the rotatablepin 57 a moves along the guide groove 57 b formed at the cassette body45 while the clamping 52 is rotatably fixed at the rotatable pin 57 a,so the region of the clamping 52 fixed by the rotatable pin 57 is fixedrather than moving according to the movement of the clamping drivingunit 51. In other words, only one end portion of the clamping 52 fixedby the fixing pin 55 moves, and at the same time, the other end portionof the clamping 52 is rotated centering around the rotatable pin 57 awhile moving along the guide groove 57 b. Accordingly, the end portionof the clamping 52 which is not fixed by the fixing pin 55 is rotated tothe region where the substrate 1 is loaded. The rotated clamping 52 isfixed to the connector 54 by the magnetic force between the firstmagnets 58 a and 58 b and the corresponding second magnets 59 b and 59c, maintaining the rotated state as it is.

When etching is completed, the clamping driving unit 51 is operated, theend portion (namely, the end portion fixed by the fixing pin 55) of theclamping 52 moves, and the rotatable pin 57 a moves again along theguide groove 57 b to allow the clamping 52 to be rotated centered aboutthe rotatable pin 57 a. Accordingly, the clamping 52 is arranged to besubstantially parallel to the cassette body 45 so as to be ready forunloading the substrate 1. In this manner, the substrate 1 can befixedly attached to, or detached from, the etching cassette 55automatically by rotating the clamping 52 by sensing the loading of thesubstrate.

With reference to FIG. 5B, a plurality of substrates 1 are fixed on theetching cassette 44. The substrate 1 first fixed on the etching cassette44 is fixed on the top of the etching cassette 44 by the second robot35. Thereafter, when the first robot 30 takes the substrate 1 out of thecassette 20 and transfers it to the second robot 35, the substrate 1 islowered as far as a pre-set distance by the second robot 35 and puts thesubstrate 1 on the etching cassette 44 fixed at a second position of thecassette fixing unit 40, and the holder 46 fixes the substrate. Thisoperation is repeatedly performed to load substrates 1 on every etchingcassettes 44 provided at the cassette fixing unit 40.

Thereafter, as shown in FIG. 5C, when the etching cassettes 44 with thesubstrates 1 loaded thereon are all fixed to the cassette fixing unit40, the cassette fixing unit 40 is rotated by 90 degrees centered aboutthe rotational shaft 41 installed at one end thereof. As the cassettefixing unit 40 is rotated, the substrates 1 which have been disposed tobe parallel to the ground are disposed to be perpendicular to theground, and in this state, the substrates 1 are inputted to the etchingapparatus along the cassette transfer unit 50 such as a guide or aconveyer, and etching is performed.

As shown in FIG. 1, the etching lines include spray plates 12 having theplurality of nozzles 13 that spray the etchant, the etchant storage tank17 for supplying the etchant to the spray plates 12, and the supply pipe12 for supplying the etchant of the etchant storage tank 17 to the sprayplates 12.

The cassette fixing unit 40 transferred along the conveyer 50 isdisposed within the etching apparatus 10 so that the etching cassettes44, namely, the substrates 1, are positioned between the spray plates 12as shown in FIG. 1. In this case, the transferred cassette fixing unit40 can be rotated according to position of the spray plates 12 of theetching apparatus 10.

In FIG. 1, the lower portions of the spray plates 12 are connected andthe spaces between the spray substrates 1 are opened at the upperportions, but without being limited thereto, the upper portions of thespray plates 12 can be connected and the spaces between the spray plates12 can be opened at the lower portions. As the spaces between the sprayplates 12 are opened at the lower portions, the cassette fixing unit 40positioned at the lower portion of the etching cassette 44 is disposedat the opened space and positioned between the spray plates 12.

When the cassette fixing unit 40 is inputted in the etching apparatusand the substrates 1 are etched by a pre-set thickness, the substrates 1are outputted from the etching apparatus in the reverse order to theorder in which the substrates 1 were inputted. Namely, when the etchingis terminated, the cassette fixing, unit 40 inputted in the etchingapparatus is outputted and returned to its original position along theconveyer 50 and the second robot 35 takes out the substrates 1 fixed atthe etching cassettes 44. The unloading of the substrates 1 is performedby the processes described with reference to FIGS. 10A and 10B.

The substrates 1 are taken out of the etching cassettes 44, mounted onthe substrate mounting part 36 of the second robot 35, returned to thefirst robot 30, and then received at the cassette 20. In this case, thesubstrates 1 discharged from the cassette fixing unit 40 aresequentially discharged, starting from the substrate 1 positioned at thelower portion of the cassette fixing unit 40.

The substrates 1 re-received in the cassette 20, namely, the etchedsubstrate 1, are transferred to undergo a follow-up process. Asmentioned above, when the substrates 1, which has finished the previousprocess, is transferred in the cassette 20, the substrate 1 isautomatically loaded to the etching cassette 44 by the first and secondrobots 30 and 35, and then inputted to the etching apparatus so as to beetched. In particular, after the substrate 1 is automatically loaded tobe fixed in the etching cassette 44, fixed at the cassette fixing unit40, and inputted to the etching apparatus in a direction perpendicularto the ground, the substrate 1 can be not only evenly etched, but alsoquickly etched.

The etching of the substrate 1 can be made such that two glass mothersubstrates are attached or by the unit of display panel. Namely, twoglass mother substrates such as the LCD or a PDP (Plasma Display Panel)can be etched in the attached state or the substrates can be etched bythe unit of attached panels. In the present disclosure, the etchingapparatus can automatically etch the substrate transferred from aprevious processing line, so by applying the etching apparatus to thefabrication line of the display panel, the fabrication line can becompletely automated. Namely, the substrate, which has undergone theprevious process, is automatically inputted to the etching line, etchedand then outputted so as to be automatically transferred to the previousfabrication line. As the fabrication line is automated, the fabricationof the display panel can be quickly made and the fabrication efficiencycan be considerably improved.

In addition, the substrate 1 can be etched by glass mother substrates orby the processed glass substrates. Namely, the glass mother substratesfabricated during the glass fabrication process are etched to a desiredweight and thickness and processed to be used as a substrate of the flatpanel display device such as the LCD. In general, the flat panel displaydevice such as the LCD includes two attached glass substrates, so itsstrength is higher than a single glass substrate. Thus, because it canbe fabricated to be thinker than when using a single glass substrate,the weight of the glass substrate can be considerably reduced. Inaddition, the glass substrate having its original thickness (withoutbeing etched) is fabricated in a glass substrate fabrication process andtransferred to the flat panel display device fabrication line and thenetched, so damage of the substrate during the transferring can beprevented.

As mentioned above, the etching apparatus according to the presentdisclosure can be applied to various flat panel display devicefabrication lines as well as for the LCD or PDP fabrication line, andthe fabrication process of the LCD will now be described as just one ofmany examples.

FIG. 11 shows the structure of a general liquid crystal display (LCD).As shown in FIG. 11, a liquid crystal panel 100 includes a lowersubstrate 103, an upper substrate 105 and a liquid crystal layer 107formed between the lower substrate 103 and the upper substrate 105. Thelower substrate 103 is a driving element array substrate. Although notshown, a plurality of pixels are formed on the lower substrate 103, andeach pixel includes a driving element such as a thin film transistor(TFT). The upper substrate 105 is a color filter substrate and includescolor filter layers for implementing an actual color. Pixel electrodesand common electrodes (not shown) are formed on the lower and uppersubstrates 103 and 105, and an alignment film for aligning liquidcrystal molecules of the liquid crystal layer 107 is coated thereon.

The lower and upper substrates 103 and 105 are attached by a sealingmaterial (or sealant) 109, between which the liquid crystal layer 107 isformed. The liquid crystal molecules driven by the driving elementformed on the lower substrate 103 are driven to control an amount oflight that transmits through the liquid crystal layer, to thus displayinformation.

The fabrication processes of the LCD can be divided into a drivingelement array substrate process for forming the driving element on thelower substrate 103, a color filter substrate process for forming colorfilters on the upper substrate 105, and a cell process. The processes ofthe LCD will now be described with reference to FIG. 12 as follows.

The method shown in FIG. 12 is a LCD fabrication process employing aliquid crystal dropping method. The liquid crystal dropping method isused for the following reasons.

In the related art, in order to form the liquid crystal layer, a liquidcrystal dipping injection method is used. According to the liquidcrystal dipping injection method, an injection hole is formed at theliquid crystal panel and liquid crystal is injected through theinjection opening to form the liquid crystal layer. In this case, theinjection of the liquid crystal is made by a pressure difference, and ingeneral, a container filled with liquid crystal is provided within avacuum chamber, the liquid crystal panel is positioned at the upperposition, and the injection opening formed at the liquid crystal panelis allowed to contact with the liquid crystal. Then, the liquid crystalis injected into the liquid crystal panel due to a pressure differencebetween the liquid crystal panel and the vacuum chamber, thereby formingthe liquid crystal layer.

However, the liquid crystal dipping injection method in which the liquidcrystal is injected through the injection opening of the liquid crystalpanel to form the liquid crystal layer within the vacuum chamber has thefollowing problems.

First, time for injecting the liquid crystal into the liquid crystalpanel is lengthened. In general, a gap between the driving element arraysubstrate and the color filter substrate of the liquid crystal panel isquite narrow, namely, a few microns, so only a very small amount ofliquid crystal is injected into the liquid crystal panel per unit time.For example, in case of fabricating a large scale liquid crystal panel,substantially tens of hours to several days are required for completelyinjecting the liquid crystal, which results a liquid crystal panelfabrication process that is lengthened by injecting the liquid crystalfor a long time, degrading the fabrication efficiency.

Second, in the liquid crystal injection method, the liquid crystalconsumption rate is high. Of liquid crystal filled in the container,only a small amount of liquid crystal is actually injected to the liquidcrystal panel. Meanwhile, when the liquid crystal is exposed in the airor to a particular gas, it is reacted on the gas so as to be degraded,and also degraded by impurities introduced when contacting with theliquid crystal panel. Thus, even when the liquid crystal filled in thecontainer is injected to a plurality of sheets of liquid crystal panels,liquid crystal remaining after injection should be discarded. Discardingof the high-priced liquid crystal causes an increase in the fabricationcost of the liquid crystal panel.

The liquid crystal dropping method is not to inject liquid crystal bythe pressure difference between the interior and exterior of the panelbut to drop and dispense liquid crystal directly onto the substrate anduniformly distribute it on the entire surface of the panel by anattachment pressure of the panel. According to the liquid crystaldropping method, the liquid crystal can be dropped directly onto thesubstrate for a short time, thus the liquid crystal layer of the largescale LCD can be quickly formed. In addition, because only the necessaryamount of liquid crystal is dropped directly on the substrate,consumption of liquid crystal can be minimized and thus the fabricationcost of the LCD can be considerably reduced.

With reference to FIG. 12, in the driving element array process, aplurality of gate lines and a plurality of data lines are formed on thelower substrate 103, defining pixel regions, and thin-film transistors(TFTs), or driving elements, are formed to be connected with the gatelines and the data lines (S101). In addition, also in the drivingelement array process, pixel electrodes are formed to be connected withthe TFTs and drive the liquid crystal layer when signals are appliedthrough the TFTs. Red (R), Green (G) and Blue (B) color filter layersfor implementing colors and common electrodes are formed on the uppersubstrate 105 in the color filter process (S104).

Subsequently, alignment films are coated on the TFT-formed lowersubstrate 103 and the color filter-layer formed upper substrate 105 andrubbed in order to provide anchoring force or a surface fixing force(namely, a pretilt angle and alignment direction) to liquid crystalmolecules of the liquid crystal layer formed between the lower and uppersubstrates 103 and 105 (S102, S105). Thereafter, liquid crystal 107 isdropped onto a liquid crystal panel region of the lower substrate 105and the sealant 109 is coated on an outer edge portion of the uppersubstrate (S103, S106).

Thereafter, in a state wherein the upper and lower substrates 103 and105 are aligned, pressure is applied thereto to attach the upper andlower substrates 105 and 103 by the sealant 109. At the same time, theliquid crystal 107 is allowed to be dropped by applying pressure touniformly spread on the entire surface of the attached substrates in theunit of mother substrates (S107).

Next, an etchant is sprayed to etch one surface or both surfaces of theattached substrates (S108). Meanwhile, a plurality of panel regions areformed on the large scale attached mother substrates and the TFTs, thedriving elements, and the color filter layers are formed at each panelregion, so in order to fabricate individual liquid crystal panels, theattached glass substrates are cut and processed so as to be divided intounit panels (S108, S109). Each unit panel is inspected to thus fabricatethe LCD (S110).

As mentioned above, the LCD is completed through the TFT array process,the color filter process and the cell process. Each process is performedat each process line. Namely, the TFT substrate and color filtersubstrates are fabricated, liquid crystal is dropped, and the sealant iscoated at the TFT array process line and the color filter process line,and the TFT substrate and the color filter substrate are attached,etched and processed into the liquid crystal panels at the cell processline. In addition, the TFT substrate line, the color filter substrateline, and the cell process line include a plurality of lines, not asingle process line, respectively.

An etching line of the substrate included in the cell process lineincludes the etching apparatus as shown in FIG. 4. The etching apparatusautomatically receives the substrate which has been processed in theprevious process, etches it, and transfers it to the follow-up process,thereby automating the cell process line.

FIGS. 13A to 13E are block diagrams of a fabrication line forfabricating the LCD according to a method for fabricating the LCDemploying the liquid crystal dropping method. FIGS. 13A and 13B areportions of the TFT line and the color filter line, respectively, andFIGS. 13C to 13E show the cell process line.

First, as shown in FIG. 13A, the lower substrate 103 with the TFTsformed at the TFT line undergoes an alignment film forming line, arubbing line, and the liquid crystal dropping line. As shown, in thealignment film forming line, the lower substrate 103 with the TFTs areformed thereon is cleaned, an alignment film is stacked thereon, whichis then heated at a high temperature. At the rubbing line, the alignmentfilm formed on the lower substrate 103 is rubbed to form the anchoringforce. In the liquid crystal dropping line, the lower substrate 103 withthe alignment film formed thereon is cleaned, on which liquid crystal isdropped.

As shown in FIG. 13B, an alignment film with an anchoring force isformed on the upper substrate 105, on which the color filter layers hasbeen formed thereon in the color filter line, at the alignment filmforming line and the rubbing line, and the sealant is for attaching thelower and upper substrates 103 and 105 is coated on outer edges of theupper substrate 105 at a sealant coating line.

In general, the alignment film forming line, the rubbing line, thedropping line, and the sealant coating line are not continuous lines.Although not shown, a means, e.g., a device such as a robot, for movingthe substrates 103 and 105 which have completed corresponding lines, isinstalled between respective process lines as shown in FIGS. 13A and13B.

The alignment film forming line and the dropping line shown in FIG. 13Aand the alignment film forming line and the sealant coating line asshown in FIG. 13B are the TFT and color filter lines. The reason forthis is because in the TFT forming process, the alignment film formingand rubbing process, and the sealant coating process are performed onthe upper substrate 106, which are independently executed on therespective substrates 103 and 105, and the follow-up process areperformed on the lower and upper substrates together.

As shown in FIG. 13C, the TFT substrate and the color filter substrateon which the alignment film was formed, liquid crystal was dropped andthe sealant was coated at the TFT line and the color filter line areinputted to an attaching line by first and second transfer units suchthat the TFT substrate and the color filter substrate are aligned.Pressure is applied to the TFT substrate and the color filter substrateso as to be attached. As pressure is applied, liquid crystal dropped onthe TFT substrate spreads to form a uniform liquid crystal layer on theentire surface of the substrate. At the same time, heat via ultravioletlight is applied to the aligned substrates to harden the sealant toattach the substrates.

As shown in FIG. 13D, the substrates 1 (attached mother substrates)which have passed through the attaching line are inputted to the etchingline and one or both sides thereof are etched by a pre-set thickness andcleaned. As shown in FIG. 4, at the etching line, the attachedsubstrates by the unit of original plates 12 received in the cassette 44transferred by a third transfer unit are automatically fixed at theetching cassette 44 by the first and second robots 30 and 35 and thenetched. After the etching, the etched substrates by the unit of originalplates are outputted in the reverse order and cleaned in a cleaningprocess.

Thereafter, the attached substrates etched at the etching line areinputted to a cutting line and cut to be divided into a plurality ofunit panels. The divided unit panels are inputted to a grinding line andgrinded and then cleaned. The grinded unit panels are inputted to aninspecting line and inspected, thereby completing the liquid crystalpanel.

As shown, as for the fabrication line of the LCD according to the liquidcrystal dropping method, the substrates undergo the alignment filmforming line, the rubbing line, the liquid crystal dropping line, thesealant coating line, the attaching line, the etching line, the cuttingline and the grinding line, to thus form the liquid crystal panels. Atthis time, the substrates are automatically transferred betweenrespective lines by using the transfer unit such as an auto-feedcarriage that transfers the cassette 44 for receiving the substrates 1,and loading or unloading the substrates 1 to or from the respectivelines are automatically performed by using the loading and unloadingunit such as the robot.

In the LCD fabrication method according to the present disclosure, oneor both sides of the attached glass mother substrates are etched by apre-set amount, so the weight of the fabricated liquid crystal panelscan be considerably reduced. In addition, because the etching line ofthe liquid crystal panel is automatedly integrated with the previous andthe following fabrication lines, the liquid crystal panels can bequickly etched.

Meanwhile, the LCD fabrication line according to the present disclosurecan be installed as the multiple lines and can be also installed at asingle line, namely, in-line. That is, on the TFT substrate and thecolor filter substrate on which the TFTs and the color filters have beenformed respectively through the TFT array process and the color filterprocess, the alignment film is coated and rubbed through the samefabrication line to provide the anchoring force to the alignment film.In addition, the forming of the alignment film, the dropping of liquidcrystal, and the coating of the sealant are performed on the TFTsubstrate and the color filter substrate at the same line. In additionand simultaneously, the substrates by the unit of the original platesare attached, etched, and processed into the unit panels. The unitpanels are then inspected as to whether they are defective or not, tothus complete the liquid crystal panels.

FIG. 14 shows the fabrication line in in-line form for performing theLCD fabrication method employing the liquid crystal dropping method. Asshown in FIG. 14, the LCD fabrication line according to the liquidcrystal dropping method includes the alignment film forming line, therubbing line, the liquid crystal dropping line, the sealant coatingline, the attaching line, the etching line, the processing line and theinspection line as one body to form a full in-line process, and as thesubstrates pass through the full in-line process, the liquid crystalpanel is completed.

The TFT substrate and the color filter substrate, on which the TFTs andthe color filter layers have been formed through the TFT process and thecolor filter process, respectively, are inputted to the alignment filmforming line to form the alignment films. In this case, any one of theTFT substrate and the color filter substrate can be first inputted, andas an example, it is assumed that the TFT substrate is first inputted.

The substrate inputted to the alignment film forming line of a firstline is cleaned, on which the alignment film is coated and then heated.When the process of forming the alignment film on the TFT substrate isterminated, the TFT substrate is inputted to a buffer line, and at thesame time, the color filter substrate is inputted to the alignment filmforming line.

The buffer line is to synchronize the TFT substrate and the color filtersubstrate. In the fabrication line according to the present disclosure,the TFT substrate and the color filter substrate are alternatelyinputted to the integrated fabrication line, on which each process isperformed, so time at which the process of the TFT substrate isterminated and time at which the process of the color filter substrateis terminated are different. In addition, time taken at the two adjacentprocesses (lines) is also different, resulting in interference betweenthe TFT substrate and the color filter substrate due to the timedifference. Thus, by storing the TFT substrate and the color filtersubstrate that have finished a single process at the buffer line for acertain time period, the TFT substrate and the color filter substrateare synchronized.

For example, when the process of forming the alignment film of the TFTsubstrate is terminated, the TFT substrate is inputted to the rubbingline and the color filter substrate is inputted to the alignment filmforming line. In this case, because a time difference occurs between theprocess time of the rubbing line and that of the alignment film inputline, the TFT substrate which has finished the alignment film formingprocess remains in at the buffer line for a certain time period.

As mentioned above, the TFT substrate which has finished the alignmentfilm forming process remains at the buffer line for a certain timeperiod and then is inputted to the rubbing line to provide the anchoringforce to the alignment film, while the color filter substrate isinputted to the alignment film forming process and then inputted to therubbing line to provide the anchoring force to the alignment film.

After the rubbing process, the dropping and sealant coating processesare separately performed on the TFT substrate and the color filtersubstrate, respectively. Thus, the TFT substrate which has undergone therubbing line is inputted to the dropping process, on which liquidcrystal is then dropped, and passes the sealant coating line as it is,namely, at which any process is not performed thereon. Meanwhile, thecolor filter substrate waits at the buffer of the rear stage of therubbing line during the dropping process of the TFT substrate. Likewise,while the TFT substrate which has finished the dropping process waits atthe buffer line of the rear stage of the sealant coating line, the colorfilter substrate is inputted to the sealant coating line and sealant iscoated on outer edges of the substrate.

It can be substantially more preferable to change the order of thedropping line and the sealant coating line. The reason for this isbecause, when the TFT substrate is first inputted, while the TFTsubstrate that has finished the rubbing process is inputted to thedropping line (passing the sealant coating line) on which the droppingprocess is performed, the color filter substrate, which has finished therubbing process, can be inputted to the sealant coating line and thesealant coating process can be performed thereon. In other words, whenthe sealant coating line is positioned at the front stage of thedropping line, the dropping line of the TFT substrate and the sealantcoating process of the color filter substrate can be simultaneouslyperformed during a certain time period, and thus, the fabricationprocess can be performed more quickly by such disposition of thefabrication line.

In addition, the sealant can be coated on the TFT substratesimultaneously with the liquid crystal being dropped to the color filtersubstrate. In this case, only the type of the substrates inputted to thedropping and the sealant coating lines is performed simultaneously;otherwise, the overall process order is the same.

The attached TFT substrate and the color filter substrate are etched bythe pre-set thickness at the etching line. In this case, the etchingline includes an etching cassette for fixing the attached TFT substrateand the color filter substrate by the unit of the original plates and acassette fixing unit for fixing the etching cassette, which is inputtedto the etching apparatus. When the attached substrates 1 by the unit ofthe original plates are loaded to the etching cassette, they are loadedinto the etching apparatus in a state of being automatically fixed bythe holder by gravity or in a state of being fixed by the operation ofthe clamping according to detecting of the sensor, etched, and thenautomatically released from the holder according to a lifting force ofthe robot or released by releasing the clamping.

The etching line is performed in-line with the previous line (namely,the liquid crystal injecting line) and with the following line(inspection line), so the cassette for transferring the attachedsubstrates 1 by the unit of the original plates is not necessary asshown in FIG. 4. Namely, in loading the substrates 1 to the etchingline, when the substrates 1 processed in the previous line areautomatically transferred by the transfer unit such as the conveyer,they are inputted to the etching apparatus by the robot. And, in loadingthe substrates 1, the attached substrates 1 from the unit of theoriginal plates 12 which have finished the etching are outputted fromthe etching apparatus 10 by the robot and then transferred to thefollowing line by using the transfer unit such as the conveyer.

In other words, in the present embodiment, when the attached substrates1 processed in the previous line are transferred sequentially to thefirst robot 30, the first robot 30 sequentially transfers the inputtedsubstrates to the second robot 35, the substrates loaded from the secondrobot 35 is fixed at the etching cassette 44, and the cassette fixingunit 40 where the etching cassette 44 is installed and inputted to theetching apparatus to perform the etching.

When the etching is finished, the substrates 1 are outputted from theetching line in the reverse order to that of the order of input to theetching line, and then transferred to the following line, namely, theprocessing line. In this case, transferring of the substrates from theprevious line to the etching line or from the etching line to thefollowing line is made by the transfer unit such as the conveyer. Theattached substrates 1 inputted to the processing line are processed bythe unit of panels, and the processed unit panels are inspected at theinspection line, thus completing the LCD panels.

As stated above, in the present disclosure, the TFT substrate and thecolor filter substrate are inputted to the integrated in-linefabrication line to complete the liquid crystal panels. Because theprocesses are performed by an integrated single line, the number offabrication lines can be reduced and thus the fabrication cost can bereduced. In addition, because a high-priced automatic transfer unit fortransferring the substrates or the liquid crystal panels between thelines is not required, the fabrication cost of the LCD can be reducedand the fabrication time can be considerably shortened.

The structure of LCD has been described limitedly in the abovedescription, but without being limited thereto, the present disclosurecan be applied to any structure of LCDs. In addition, the presentdisclosure is not limited to etching of a particular substrate, but canbe used for etching glass mother substrate, attached glass mothersubstrates, processed glass substrate, and attached unit panels.

In addition, the present disclosure can be applied to fabricationmethods of various flat panel display devices such as PDP, FED, VFD,OLED, and the like. As so far described, according to the presentdisclosure, the substrates and the liquid crystal panels are etched tohave the pre-set thickness, the weight of the LCD can be considerablyreduced. In addition, because etching of the substrates and the liquidcrystal panels is automatically performed at the fabrication line, thesubstrates and the liquid crystal panels can be quickly etched.

As the present disclosure may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the metes and bounds of theclaims, or equivalents of such metes and bounds are therefore intendedto be embraced by the appended claims.

1. A fabrication line of a liquid crystal display comprising: a thin film transistor (TFT) line that receives a first substrate and forms TFTs; a color filter line that receives a second substrate and forms color filter layers; a dropping line that drops liquid crystal onto the first substrate; an attaching line that attaches the first and second substrates to form a liquid crystal layer; and an etching line that etches the attached first and second substrates, wherein a transfer unit is provided between the TFT line, the color filter line, the attaching line, and the etching line to transfer the process-finished substrate to each follow-up process.
 2. The fabrication lien of claim 1, wherein the attaching line comprises: an attaching line that attaches the first and second substrates by a sealant to form the liquid crystal layer; and a hardening line that hardens the sealant.
 3. The fabrication line of claim 1, further comprising: a first alignment film forming line that receives the first substrate and forms a first alignment film with an anchoring force formed thereon; and a second alignment film forming line that receives the second substrate and forms a second alignment film with an anchoring force formed thereon.
 4. The fabrication line of claim 2, wherein the second alignment film forming line comprises a sealant coating line that coats the sealant on the second substrate.
 5. The fabrication line of claim 1, further comprising: a cutting line that cuts the etched substrate to form a unit panel.
 6. The fabrication line of claim 1, further comprising: an inspection line that inspects the unit panel with the liquid crystal layer.
 7. The fabrication line of claim 1, wherein the etching line comprises: a cassette to receive the first and second substrates attached at the attaching line and transferred by a transfer unit; a first robot to take the attached first and second substrates out of the cassette; a second robot to receive the attached first and second substrates from the first robot so as to be mounted thereon and that is movable vertically up and down; an etching cassette comprising a support to support the attached first and second substrates and a substrate fixing unit to fix the first and second substrates loaded by the second robot; a cassette fixing unit to fix at least one or more etching cassettes and rotated at a pre-set angle to allow a unit panel to be disposed vertically; and an etching apparatus for etching the first and second substrates disposed vertically by the cassette fixing unit.
 8. The fabrication line of claim 6, wherein the fixing unit comprises a holder that is contracted by gravitational effects of the substrate, lowered by the robot to allow the substrate to pass therethrough and then restored to fix the substrate.
 9. The fabrication line of claim 7, wherein the fixing unit comprises: a plurality of clampings disposed in at least both sides of the etching cassette to fix the loaded substrate; and a clamping driving unit to rotate the clampings, to fix the substrate.
 10. The fabrication line of claim 9, wherein the fixing unit comprises: a fixing pin to fix one end portion of the clamping to the clamping driving unit; a rotatable pin to rotatably fix the clamping to the etching cassette; and a guide groove defined on the etching cassette to enable the rotatable pin to move therealong.
 11. The fabrication line of claim 7, wherein the first robot comprises: a robot arm to take the first and second substrates out of the cassette; and a rotational shaft to transfer the extracted first and second substrates to the second robot.
 12. The fabrication line of claim 7, wherein the second robot comprises: a substrate mounting part to enable the first and second substrates to be mounted thereon; and an extending shaft that moves vertically up and down.
 13. The fabrication line of claim 7, wherein the etching apparatus comprises: a plurality of spray plates disposed vertically, at least one surface thereof being adjacent to the attached first and second substrates, and having an etchant filled therein; and a plurality of nozzles disposed on the spray plates to spray the etchant onto the attached first and second substrates.
 14. A fabrication line of a liquid crystal display comprising: a liquid crystal dropping line that receives a first substrate and drops liquid crystal onto the first substrate; a sealant coating line that receives a second substrate and coats a sealant; an attaching line that receives and attaches the first and second substrates; and an etching line that etches the attached first and second substrates, wherein the liquid crystal dropping line, the sealant coating line, the attaching line, and the etching line are integrated.
 15. The fabrication line of claim 14, further comprising: an alignment film forming line that alternately receives the first substrate on which the liquid crystal is dropped and the second substrate on which the sealant is coated and forms an alignment film with an anchoring force formed thereon.
 16. The fabrication line of claim 15, wherein the alignment film forming line comprises: an alignment film coating line that coats the alignment film on the first and second substrates which are alternately inputted; a heating line for heating the coated alignment film; and a rubbing line that rubs the heated alignment film to determine an alignment direction.
 17. The fabrication line of claim 14, further comprising: a processing line that receives the attached first and second substrates and divides the attached first and second substrates into a plurality of unit panels.
 18. The fabrication line of claim 14, wherein the first substrate is a thin film transistor (TFT) substrate on which TFTs are formed and the second substrate is a color filter substrate on which color filter layers are formed.
 19. The fabrication line of claim 14, wherein at least one buffer line is installed between respective lines in order to synchronize the first and second substrates.
 20. The fabrication line of claim 14, further comprising: an inspection line that inspects the divided unit panels.
 21. The fabrication line of claim 14, wherein the etching line comprises: a cassette to receive the first and second substrates attached at the attaching line and transferred by a transfer unit; a first robot to take the attached first and second substrates out of the cassette; a second robot to receive the attached first and second substrates from the first robot so as to be mounted thereon and movable vertically up and down; an etching cassette comprising a support to support the attached first and second substrates and a substrate fixing unit to fix the first and second substrates loaded by the second robot; a cassette fixing unit to fix at least one or more etching cassettes and rotated at a pre-set angle to allow the attached first and second substrates to be disposed vertically; and an etching apparatus for etching the first and second substrates disposed vertically by the cassette fixing unit.
 22. The fabrication line of claim 21, wherein the fixing unit comprises a holder that is contracted by gravitational effects of the substrate, lowered by the robot to allow the substrate to pass therethrough and then restored to fix the substrate.
 23. The fabrication line of claim 21, wherein the fixing unit comprises: a plurality of clampings disposed in at least both sides of the etching cassette to fix the loaded substrate; and a clamping driving unit to rotate the clampings, to fix the substrate.
 24. The fabrication line of claim 21, wherein the fixing unit comprises: a fixing pin to fix one end portion of the clamping to the clamping driving unit; a rotatable pin to rotatably fix the clamping to the etching cassette; and a guide groove defined on the etching cassette to enable the rotatable pin to move therealong.
 25. The fabrication line of claim 21, wherein the first robot comprises: a robot arm to take the first and second substrates out of the cassette; and a rotational shaft to transfer the extracted first and second substrates to the second robot.
 26. The fabrication line of claim 21, wherein the second robot comprises: a substrate mounting part to enable the first and second substrates to be mounted thereon; and an extending shaft that moves vertically up and down.
 27. The fabrication line of claim 21, wherein the etching apparatus comprises: a plurality of spray plates disposed vertically, at least one surface thereof being adjacent to the attached first and second substrates, and having an etchant filled therein; and a plurality of nozzles disposed on the spray plates to spray the etchant onto the attached first and second substrates. 